Rotation describes the position of the image intensifier around the longitudinal axis of the patient. LAO refers to rotating the camera to the patient's left (catheter and spine will be on the right side of the image), RAO to the patient's right (catheter and spine on the left side of the image). Angulation describes the position of the image intensifier in the short axis of the patient. Camera can pivit toward (cranial) or away (caudal) from the patient's head
For the beginner angiographer the anatomic landmarks formed by the spine, catheter and diaphragm provide information to discern which tomographic view from which the image is obtained. In the LAO view the catheter and spine are seen on the right side of the image, while in the RAO they are found on the left. PA imaging places these landmarks in the center of the image. Cranial angulation can usually be distinguished from caudal angulation by the presence of the diaphragm. For cranial imaging, the patient should be asked to inspire to remove the diaphragmatic shadow from the image.
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